Author Chris Brookmyre on creating Scotland's answer to Miss Marple for his latest thriller

Penelope Coyne, the new character introduced at the start of Chris Brookmyre's new crime thriller, would appear to have more than a few things in common with Miss Marple.

Agatha Christie's famous creation may have tackled dozens of cases, but none of them involved her being thrown together with a hard-bitten Los Angeles homicide detective.

But that's exactly what unfolds in The Cracked Mirror, the Glasgow-born author's latest novel, which brings a tea-drinking retired librarian together with hard-drinking, rule-breaking maverick Johnny Hawke and brings machine guns and a high-speed car chase through the fictional village of Glen Cluthar.

The author may have had "great fun" playing the two vastly different characters off each other, but admits his latest book proved his toughest yet to produce, with around six months of planning and plotting before he even started writing.

Brookmyre was intrigued by the possibilities of combining two "very different flavours" of crime fiction.

He recalled: "I always get excited if I think I’m doing something that no-one else has done or no-one else would even attempt.

“As a crime or genre writer, there are times when you think ‘this is okay, but I know half a dozen writers that would do this better than me.’

"I’m always at my happiest when I’m doing something and thinking ‘no-one else is doing this.’

"I started writing The Cracked Mirror in late January last year but spent around six months fleshing out the concept, the plot, the structure and who these characters were before I wrote the first page."

Brookmyre has forged an acclaimed writing partnership with his wife Dr Marisa Haetzman, a consultant anaesthetist, in recent years to create a series of historical crime thrillers set in Victorian Edinburgh, published under the pseudonym Ambrose Parry.

The couple joined forces again on The Cracked Mirror during a "working holiday," during which Brookmyre tested out his concept for a story that not only combines crime genres but also features his trademark twists as the action switches between America and Scotland, as the unlikely partnership investigates the links between a number of sudden deaths with odd similarities.

Brookmyre said: "Marisa and I do a lot of prep before we work on an Ambrose Parry book, so we know the story fairly well before we start writing it.

"Some of that is down to experience, but some of it is down to the fact that Marisa has knocked me into shape. She likes far more structure and a road map of where we’re going. I've realised that there's so much more you can do with the story if you plan it out more.

"Part of that working holiday was me explaining the concept for The Cracked Mirror and Marisa helping me refine it. When we work together, she often points out where something doesn’t make sense.

"It's often something that seems to make a lot of sense in my head, but as soon as I explain it I realise there’s a lot of gaps in it."

As well as the obvious nods to Miss Marple, Brookmyre also cites Michael Connell's LA detective Harry Bosch and the work of screenwriter Shane Black as major inspirations for The Cracked Mirror.

He said: "I wanted to have someone with a rigid sense of order and rules, and then contrast that with the classic maverick cop who always wants to break the rules.

"Penny is a retired librarian who has a very keen attention to detail and what should be right, she susses that things are wrong, and has got very strong reasons for why she thinks rules should always be observed.

"If there’s one criticism I’d have when it comes to the Miss Marple stories it’s that she is seldom in much peril - emotionally, physically or financially.

"At the start of The Cracked Mirror, Penny gets an invitation to a wedding, but the names of the bride and groom are not familiar. She is disturbed by the fact that this might be because she is having memory problems.

"If your whole raison d'etre is solving murders through the most precise reading of small details the prospect of losing your memory is absolutely horrifying.

"Johnny is the classic maverick cop, who is always in trouble with his captain and his partners are like the drummers in This Is Spinal Tap - they don’t last very long. He’s asked to investigate a politically-sensitive suicide at a movie studio. His softly-softly approach ends up in it being completely burned down to the ground."

Brookmyre admits he found it tricky to write in two "very different styles" in the early chapters of The Cracked Mirror, which he will be launching at The Portobello Bookshop in Edinburgh on Tuesday and the Drygate Brewery in Glasgow on Wednesday.

He said: "To have to write with a different tone for each character so that it feels like a different novel was quite challenging.

"But with that established it was great fun to play with the way their two worlds contrast. When Johnny then turns up in Penny’s world that was obviously fun too.

"The type of murders she is dealing with have altered, there is a kind of visceral horror to them that wasn’t there before. It’s like her world has been infected by Johnny turning up.

"I was determined that they wouldn’t get along and thought it would be good if they were suspicious of each other initially.

“It has a classic structure of two mismatched investigators who don’t get along but have to become a wee bit like each other in order to get to the bottom of the mystery."